In enterprise applications, achievable user density in wireless voice communications is an important figure of merit, both for systems using Bluetooth protocols as well as other packet-based radio systems. One factor adversely impacting achievable user density is interference. For example, since the first release of the standard in 1999, the Bluetooth wireless technology has seen a major uptake for use in short-range communications. Making use of unlicensed spectrum in the 2.4 GHz ISM band, Bluetooth must share the spectrum with other users, including other Bluetooth users. Being an ad-hoc system, Bluetooth does not coordinate its communication with other systems. Instead, it relies on its frequency hopping capability to deal with interference.
In a typical enterprise usage scenario, numerous base stations are located within a building space. To each base station, a single headset is connected, together forming an independent piconet. The headsets are scattered around the base stations. A frequent topic of discussion is the density of users that can be achieved without noticeable interference, with higher user density naturally being the goal. In Bluetooth, voice is compressed and sent in a series of short packets to the receiver. A packet may be interfered by packets from other Bluetooth transmitters, or by signals from other transmitters in the ISM band. For example, one major source of interference in the 2.4 GHz ISM band is the WiFi system based on the IEEE 802.11 standard. Factors affecting whether a packet is interfered with and lost include (1) the strength of the interference power with respect to the strength of the intended received power, (2) whether the packets (partly) overlap in time, and (3) whether the packets make use of the same (or near-adjacent) carrier frequency. As use of packet-based radio systems continues to increase, improved technologies, methods, and apparatuses for packet-based radio systems are needed.